Season 6: Episode 4: Memory Lane

In 226, the USS Archeron was lost. It vanished without a trace. All hands were listed as MIA.
But in 2396, it was found floating in a nebular. All hands were in suspended Animation. The crew was slowly revived and sent to DS34 for healing, counselling and reassignment. Now as the USS Elysium slowly makes it's way back home via another Galaxy, something is stirring.

A young child wakes screaming in her cabin, and throughout the ship nightmares become prevalent.